Offshore drilling rig



July 8, 1941.

W/T/VESS:

E. R. ARMSTRONG 2,248,051

OFFSHORE DRILLING RIG 5 sheets-sheet 1 Filed Dec. 28, 1958 9m 7%. a 1M52 M J l 5 LIN B e e w Pl 2, w 2 m M s a 5 W G $8 L2 SI. ll M MW I REDAmm EM M 0 1L w W 8 ..W h

y 1941. E. R. ARMSTRONG 2,248,051

OFFSHORE DRILLING RIG Filed D66. 28, 1938 5 Sheets-Sheet 3 y 1941- E. R.ARMSTRONG 2,248,051

OFFSHORE DRILLING RIG Filed Dec. 28, 1938 5 Sheets-Sheet 4 W/T/VESS.

Patented July 8, 1941 UNITED STATES PATENT OFFICE OFFSHORE DRILLING an;

Edward R. Armstrong, New York, N. 1., assignor to Sun Oil Company,Philadelphia, Pa., a corporation of New Jersey Application December 28,1938, Serial No. 248,051

11 Claims.

The present invention relates to an apparatus for drilling oil wells oiishore, and particularly to an apparatus which may readily be transportedfrom place to place and placed in position for drilling.

It has heretofore been proposed, when drilling in shallow inland waters,to provide a barge having a superstructure thereon capable of supportingthe full load of the drilling equipment, to tow such barge to thelocation at which the well is to be drilled, and, by flooding the barge,sink it this purpose.

to position on the bottom so that a deck on the superstructure uponwhich drilling equipmentis mounted remains above the water line. Such astructure is shown in the Giliasso Patent No. 1,681,533, issued. August21, 1928.

It is readily discernable that such a structure has its limitations inthat the drilling equipment must be very evenly distributed over thedeck in order that the barge may be sunk to the bottom without tiltingor capsizing. In practice it has been impracticable to provide astructure which is capable of holding a drilling rig and the necessarypower supply means whether such power supply means he steam boilers orDiesel generator sets. It is also apparent that the depth of water inwhich a well may be drilled with such and other weather conditions.

It is also the further object of this invention to provide a structurewhich may readily be used with the heaviest of drilling equipment andthe tallest of derricks in order to provide a floating yet stablestructure capable of drilling wells of between 10,000 to 15,000 feet indepth. In accordance with the present invention, a plurality of circularpontoons are provided, each pontoon preferably being provided with acircular aperture through which a spud or column having an enlargedbottom extends. The enlarged bottom of the spud or column extends upinto the pontoon so as to be flush with the bottom surface thereof,providing a structure which may be readily towed through shallow waters.These spuds or columns may be lowered or raised relative to the pontoonsby varying the buoyancy of each spud column by pumping in or out thenecessary water to give each spud column the buoyancy desired. When therelative position or each spud column in its pontoon is that desired,and obtained by buoyancy control of the spud column as outlined, eachcan be locked in position by suitable looking or clamping devicesprovided for Thus, when it is desired to operate the drilling rig todrill awell, the water is admitted to each of the spud columns so thatthey sink until they come firmly to rest on the ocean bed. They arethenlocked in this position and controlled amounts of water thenadmitted to the main pontoon system thereby reducing its buoyancy andincreasing weight supported by the spud columns to that desired therebycausing them to provide a firm foundation for the structure. The pontoonsystem is held together by a truss system on which is built the drillingstructure consisting of two or more decks carrying drilling and powerequipment anda drilling derrick.

It is an object of the present invention to provide a floating structurecapable of being partially supported by spuds or columns extending tothe bottom of the water in which the structure is being used. 7

It is also an object of the present invention to provide a structurecomposed of a plurality of pontoons held together in' a unitarystructure by a truss system on which 'is supported complete drilling andpower equipment 101* drilling wells from two to three miles in depth.

It is also an object of the present invention to provide a structurewhich may be readily refloated and removed to another location after thecompletion of a well.

In order that a better understanding of the invention may behad,reference, is made to the accompanying drawings in which:

Fig. 1 is an outboard profile of the structure in towing condition;

Fig. 2 is alongitudinal section taken through Fig. 1 and showing thestructure in position for drilling in shallow. water;

Fig. 3 is a transverse section through line 3-3 of Fig. l-showing thesame structure in position for drilling in deep water;

Fig. 4 is a section taken on line 4-4 of Fig. 1 showing the top only ofthe upper buoyancy tanks and the deck trusses.

Fig. 5 is a section taken on line 5-5 of Fig. 1 showing the top of thelower buoyancy tanks and the struts for holding the same in one unitarystructure.

Fig. 6 is a plan view of the upper deck; and

Fig. '7 is .a plan view of the lower deck.

Referring now to the drawings, It] indicates the main or lower buoyancytanks which in the em bodiment illustrated are eight in number, andwhich have circular recesses H therein arranged to accommodate theenlarged bottoms l2 of the spuds or columns l3. The lower edges of thebottoms l2 are relatively sharp and capable of penetrating into the seabottom. A valve 40, which may be operated from the top of the column isprovided in or near the bottom of each of the spuds l2 for admitting orremoving water thereto, while a valved line 4i communicates with theinterior of each of the columns near the top thereof for venting airtherefrom or admitting compressed air into the column to control theheight of water therein and thus control their buoyancy. By referencetoFig. it will be noted that the recesses ll are eccentric to the circularpontoons or tanks in and are placed as near to the outside of theunitary structure as possible. Locking means are provided for lockingthe columns l3 in raised or lowered position. The pontoons or tanks H)are joined together by diagonal struts l4 and by longitudinal andtransverse struts l5 and IS. The two central longitudinal struts l1 anddiagonal struts l8 are arranged to be readily removed in order topermitthe structure to be floated away from the well after the same has beencompleted.

Immediately above the buoyancy tanks ill are placed the upper buoyancytanks l3 which are securely fixed, as by welding, to the buoyancy tanksill, the upper tanks l9 being provided with circular passagestherethrough for the accom,

modation of the spudsor columns l3. Each of the tanks I9 is providedwith a suitable locking device 20 for securely clamping the column inany desired position. The upper buoyancy tanks carry a truss system 2|,which, together with the strut system I 5, I6, I! and I8 joins thestructure so as to provide a solid structure for the drilling equipment,power supply, etc., whether the structure is in its entirely buoyantposition or is partially supported by the spuds I3 resting on thebottom. 7

On the truss system 2| there is supported a lower deck 22 and an upperdeck 23. Between the four central upper buoyancy tanks I 9 and the lowerdeck are provided two tanks 24 and 25 which are partitioned to providein all four tanks, one of which is used as the active mud pit, anotheras the reserve mud pit, the third as a fresh water storage tank and thefourth as a fuel oil storage tank. On thelower'deck there is placed thepower equipment 26 (Fig. 7) consisting, for example, of a Dieselelectric plant and the various pumps and compressors necessary to thedrilling operations. 'On the top deck is supported a derrick 21,together with the draw works 28 for a drill operating through casing aswell as two derricks 23 and 30 for transporting material above thestructure or lifting it from a service boat on to the structure.

The necessary auxiliary drilling equipment and service facilities may bedistributed about the upper deck 23 and lower deck 22 of thesuperstructure, a suggestive arrangement being diagrammaticallyillustrated in Figs. 6 and 7. Thus, in addition to the draw works 28,acoring reel to the power plant 25, may be placed slush pumps 35,aircompressor 36, mud mixer 31 and shale shaker 33. Any other necessaryor desirable equipment may be placed on the decks. In arranging theequipment on the decks, it is desirable that the load be distributed asevenly as possible in order to trim the apparatus. However, in case ofeccentric loading, it is possible to admit water to certain of thebuoyancy tanks and thereby cause the apparatus to float on an even keel.

The operation of the apparatus is as follows:

The entire apparatus with the columns l3 raised so that the spuds i2 arewithin the floats I0 is towed to the site of the drilling operation.Assuming that the drilling rig is floating level at its proper draft,the columns l3 are unlocked by releasing the locking devices 20 andwater is gradually admitted to each of the spud columns so that theysink until the enlarged bottoms or in the bed or floor of the ocean asfar as they will go and the columns I3 are then locked in their loweredposition by means of the mechanical locking devices 20. A controlledamount of water is then admitted to the lower buoyancy tanks l0 therebylessening their buoyancy and increasing the weight supported by thecolumns l3 to that desired and driving the spuds l2 firmly into thefloor of the ocean. Suflicient water is admitted to the lower buoyancytanks ill to firmly anchor the apparatus and to cause the columns l3 toprovide a firm foundation for the structure. As the apparatus settles inthe water, theupper buoyancy tanks l9 are partially submerged so thatthey support a portion of the weight of the apparatus by theirdisplacement of water while the columns I3 support only the differencebetween the total weight of the apparatus and the effective buoyancy.

Once the apparatus has been positioned at the site chosen for drilling,the regular drilling equipment is operated in the manner customary whenoperating on land and the well is drilled in the usual manner, thenecessary supplies and equipment being transported to the apparatus byservice boats and being used in the usual manner. At the completion ofthe drilling at the given site, piles may be drivenfrom the decks of theapparatus and a suitable structure erected on the piles for supportingany necessary surface equipment such as the customary Christmas treesfor controlling the wellswhen flowing, and means, such as pipe lines, onthe floor of the ocean, may be provided for handling the oil. Allconnections between the derrick and the well may then be severed and thewell connected to the usual surface connections provided on the pile orother foundation which has been built. The entire apparatus may then berefioated by forcing water out of the lower buoyancy tanks or pontoonsl0, thereby increasing their buoyancy and causing them to support theentire weight of the apparatus, taking any load Off the columns or spudsl3 and raising the spud shoes it from the bed of the ocean. The spuds orcolumns l3 may then be raised by forcing the water out of them either bypumping or by means or compressed air, thereby causing them to be raisedby their buoyancy so that the shoes or bottoms l2 thereof enter therecesses provided therefor in the pontoons in after which the columnsmay be locked in their raised position by locking device 20. Theapparatus may then be towed to another drilling site.

From the above description, it is apparent that; I have provided anapparatus which may be floated into position over a proposed under waterdrilling site. The apparatus may be firmly anchored to the bottom and isnot affected by the action of waves. Furthermore, the apparatus providesa self-contained drilling structure with ample room for all necessaryequipment and activity connected with oil well drilling and with amplespace for the storage of reserve supplies or equipment.

No attempt has been made in the specification to describe the drillingapparatus per se in detail, since it is contemplated that the customarydrilling apparatus will be used. Likewise, the arrangement of thenecessary drilling and aukiliary equipment on the decks of the apparatusillustrated in Figs. 6 and 7 is merely suggestive and not limiting andany suitable arrangement may be used. Various other modifications may bemade in the design of the apparatus without departing from the spirit ofmy invention or the scope of the appended claims.

What I claim and desire to protect by Letters Patent is:

1. An offshore drilling rig comprising a superstructure adapted tosupport a derrick structure,

a plurality of horizontally spaced independent buoyancy units connectedin spaced relation to said superstructure and supporting the same, meansfor regulating the buoyancy of said units, a plurality of longitudinallymovable vertical columns supported by said superstructure and means forlocking said columns in a vertically adjusted position in extensionbelow the buoyancy units respectively. 7

2. An offshore drilling rig comprising a superstructure adapted tosupport a derrick structure, a plurality of horizontally spacedindependent buoyancy units connected in spaced relation to saidsuperstructure and supporting the same, each of said buoyancy unitscomprising a lower enlarged closed pontoon of relatively largehorizontal cross-section and an upper closed buoy-- ancy tank ofrelatively smaller horizontal cross section than said pontoon, saidpontoons having sufficient buoyancy for supporting the entire apparatus,a plurality of longitudinally movable vertical columns supported by saidsuperstructure and means for locking said columns in a verticallyadjusted position in extension below the buoyancy units respectively.

3. An offshore drilling rig comprising a superstructure adapted tosupport a derrick structure,

a plurality of horizontally spaced buoyancy units connected to andsupporting said superstructure,.

each of said buoyancy units comprising an'annular closed tank, avertical column extending through an opening in each of said buoyancyunits and movable longitudinally therethrough and means for locking saidcolumns with respect to said buoyancy units.

4. An oifshore drilling rig comprising a superstructure adapted tosupport a derrick structure, a plurality of horizontally spaced buoyancyunits connected to and supporting said superstructure, each of saidbuoyancy units comprising a lower annular closed tank of relativelylarge horizontal cross section, said tanks having suflicient buoyancy tosupport the entire apparatus and an upper annular closed tank ofrelatively small horizontal cross section, means for admitting water tosaid lower tanks, a vertical column extending through an opening in eachof said buoyancy units and movable longitudinally therethrough and meansfor locking said columns in position.

5. An offshore drilling rig comprising a superstructure adapted tosupport a derrick structure, a plurality of horizontally spaced buoyancyunits connected to and supporting said superstructure, each of saidbuoyancy units comprising a lower annular closed tank of relativelylarge horizontal cross section, said tanks having suflicient buoyancy tosupport the entire apparatus and an upper annular closed tank ofrelatively small horizontal cross section, means for admitting water tosaid lower tanks, a vertical column extending through an opening locatedeccentrlcally in each of said buoyancy units and movable longitudinallytherethrough and means for locking said columns in position.

6. An offshore drilling rig comprising a superstructure adapted tosupport a derrick structure, a plurality of horizontally spaced buoyancyunits connected to and supporting said superstructure, each of saidbuoyancy units comprising an annular closed tank, a. vertical columnextending through an opening in each'of said buoyancy units and movablelongitudinally therethrough, an enlarged bottom on each of said columns,a recess in the bottom of each of said buoyancy units adapted to receivesaid enlarged bottom of said columns, and means for locking said columnsin position.

7. An offshore drilling rig comprising a superstructure adapted tosupport a derrick structure, a plurality of horizontally spacedindependent buoyancy units connected in spaced relation to saidsuperstructure and supporting the same, means for'regulating thebuoyancy of said units, a plurality of longitudinally movable verticalcolumns supported by said superstructure, said columns being adapted tobe lowered to engage the bottom to anchor said buoyancy units and meansfor locking said columns in lowered position.

8. An offshore drilling rig comprising a superstructure adapted tosupport a derrick structure, a plurality of horizontally spaced buoyancyunits connected to and supporting said superstructure, each of saidbuoyancy units comprising an annular closed tank, a vertical columnsupported from each of said buoyancy units and movable longitudinallywith respect thereto and means for locking said columns with respect tosaid buoyancy units.

9. An offshore drilling rig comprising a superstructure adapted tosupport a derrick structure, a plurality of horizontally spacedindependent buoyancy units connected in spaced relation to saidsuperstructure and supporting the same, means for regulating thebuoyancy of said units, a longitudinally movable vertical columnextending through each of saidbuoyancy units, said columns being adaptedto be lowered to engage the bottom to anchor said buoyancy units andmeans for locking said columns in lowered position.

10. An offshore drilling rig comprising a superstructure adapted tosupport a derrick structure, a plurality of longitudinally movablevertical columns supported by said superstructure and adapted to engagethe bottom of a. body of Water upon which the rig may float, each saidcolumn having a water-tight compartment formed interiorly thereof, meansfor flooding and emptying said compartment to raise or lower said umnssupported by said superstructure and "10 adapted to engage the bottom ofa body of water upon which the rig may float, each said column having awater-tight compartment formed interiorly thereof, means for floodingand emptying said compartment to raise or lower said column, and meanstor locking said columns in a vertically adjusted position in extensionbelow the superstructure.

EDWARD R. ARMSTRONG.

